Histone demethylase JMJ713 interaction with JMJ708 modulating H3K36me2, enhances rice heat tolerance through promoting hydrogen peroxide scavenging

The Earth is currently undergoing rapid warming cause of the accumulation in greenhouse gas emissions into the atmosphere and the consequent rise in global temperatures. High temperatures can bring the effects on rice development and growth and thereby decrease rice yield. In this study, we have identified that both JMJ713 and JMJ708 possess distinct histone demethylase activities. Specifically, JMJ713 modulates the levels of H3K36me2 while JMJ708 alters H3K9me3. Additionally, we have observed an interaction between JMJ713 and JMJ708, which collectively modify the level of H3K36me2. Furthermore, our findings demonstrate that JMJ713 plays an essential role to heat stress responses in rice (Oryza sativa). The overexpression of JMJ713 enhances heat tolerance in rice, whereas JMJ713 RNA interference rice lines exhibit increased sensitivity to heat. Further investigations revealed that overexpression of JMJ713 activated catalase (CAT) and peroxidase (POD) activities by mitigating excessive accumulation of reactive oxygen species (ROS) caused by heat stress. Interestingly, the setting rates of JMJ713 RNA interference lines decreased in comparing to wild-type, indicating that JMJ713 might play a crucial role in the rice seed development stage as well. Collectively, this study not only highlights JMJ713 is involved in heat stress responses but also provides insights into the conserved Fe(Ⅱ) and α-ketoglutarate (KG) binding residues are crucial for the demethylase activity of JMJ713, as well as JMJ713 interacts with JMJ708 to jointly regulate the levels of H3K36me2.